Taking advantage of extra solar energy collected during the day, NASA's
Mars Exploration Rover Spirit settled in for an evening of stargazing,
photographing the two moons of Mars as they crossed the night sky. This
time-lapse composite, acquired the evening of Spirit's martian sol 590
(Aug. 30, 2005) from a perch atop "Husband Hill" in Gusev Crater, shows
Phobos, the brighter moon, on the left, and Deimos, the dimmer moon, on
the right. In this sequence of images obtained every 170 seconds, both
moons move from top to bottom. The bright star Aldebaran forms a trail on
the right, along with some other stars in the constellation Taurus. Most
of the other streaks in the image mark the collision of cosmic rays with
pixels in the camera.
Scientists will use images of the two moons to better map their orbital
positions, learn more about their composition, and monitor the presence
of nighttime clouds or haze. Spirit took the six images that make up this
composite using Spirit's panoramic camera with the camera's broadband
filter, which was designed specifically for acquiring images under
low-light conditions.